1. Field of the Invention
The present invention relates to a toner for use in an image forming method such as an electrophotographic method.
2. Description of the Related Art
Image forming apparatuses using an electrophotographic method, such as printers and copiers, are demanded to achieve further speeding up and energy saving, and it is effective for achieving speeding up and energy saving to enhance the low-temperature fixability of a toner. On the other hand, printers and copiers have been used for various purposes in recent years, and have been increasingly performing output on various sizes of paper sheets frequently. On the other hand, problems along therewith have been easily caused.
For example, when small-sized paper sheets are continuously fed to a fixing unit and then larger-sized paper sheets than the small-sized paper sheets are fed thereto, the following problem occurs: the small-sized paper sheets are continuously fed to thereby result in the increase in temperature of an area of the fixing unit, through which no paper sheets are allowed to pass, easily causing so-called end-portion hot (or high temperature) offset to occur.
Even if the low-temperature fixability of a toner can be enhanced to allow the preset temperature of a fixing unit to be lower than the preset temperature of a conventional unit, the increase in temperature of the end portion of the fixing unit cannot be avoided in continuous feeding of the small-sized paper sheets, and hence it is also important to enhance the hot offset resistance of a toner. In order to satisfy the hot offset resistance, various toners have been proposed.
In Japanese Patent Application Laid-Open No. 2011-501231, a toner into which a crosslinkable resin is incorporated for improvement in the hot offset has been proposed. In Japanese Patent Application Laid-Open No. 2011-002653, a toner into which resin particles having a softening temperature higher than the softening temperature of a binder resin is incorporated has been proposed. Both of the documents, however, can be insufficient in terms of the hot offset resistance with an end portion focused.